Preparation method of ethoxypentafluorocyclotriphosphazene

Abstract

The invention relates to a preparation method of ethyoxyl pentafluorocyclotriphosphazene. The preparation method comprises the following steps: S1, dissolving hexafluorocyclotriphosphazene in a solvent, and preparing a hexafluorocyclotriphosphazene solution at the temperature of-20 to 10 DEG C; s2, ethanol salt is dissolved in a solvent to prepare an ethanol salt solution, and the temperature of the ethanol salt solution is reduced to-20 DEG C to 10 DEG C; s3, adding the ethanol salt solution into the hexafluorocyclotriphosphazene solution according to a certain rate, stirring and reacting at the reaction temperature of-20 to 10 DEG C for 2 to 5 hours; s4, after the reaction in the step S3 is finished, carrying out solid-liquid separation on the reaction liquid, drying and recovering solid substances, and collecting all the reaction liquid; and S5, sequentially carrying out rotary distillation and vacuum rectification on the reaction liquid under the protection of inert gas to obtain the product ethoxypentafluorocyclotriphosphazene. The ethoxypentafluorocyclotriphosphazene prepared by the method is high in conversion rate, good in yield, short in reaction time, simple to operate and high in low-temperature reaction safety coefficient.

Description

Technical Field

[0001] The invention relates to the technical field of a preparation method of ethoxy pentafluorocyclotriphosphazene, and relates to a synthesis and separation and purification process of ethoxy pentafluorocyclotriphosphazene, and specifically refers to a preparation method of ethoxy pentafluorocyclotriphosphazene. Background Art

[0002] Oxypentafluorophosphazene is often used in lithium-ion batteries because it contains two flame-retardant elements, phosphorus and fluorine, which have a synergistic effect with each other. Adding a small amount of ethoxypentafluorophosphazene to the electrolyte of lithium-ion batteries can not only reduce the use of other additives, improve the flame retardant efficiency, and improve the charge and discharge cycle performance of the electrolyte, but also prevent various safety hazards caused by battery abuse and overcharging. Therefore, ethoxypentafluorocyclotriphosphazene has broad application prospects in the field of lithium-ion battery electrolytes.

[0003] At present, the methods for preparing ethoxy pentafluorocyclotriphosphazene can be roughly divided into two categories. One is to first etherify hexachlorocyclotriphosphazene into ethoxy pentachlorocyclotriphosphazene, and then use fluoride salt for nucleophilic substitution to become ethoxy pentafluorocyclotriphosphazene; the other is to prepare hexachlorocyclotriphosphazene starting with phosphorus pentachloride, then use fluoride salt for nucleophilic substitution, and finally use ethanol salt for etherification reaction to prepare ethoxy pentafluorocyclotriphosphazene. However, the number of domestic enterprises that can prepare ethoxy pentafluorocyclotriphosphazene and sell it is not only small, but also the preparation process is complicated, there are many by-products, low conversion rate, low yield, and uneven product quality, and the use of sodium fluoride and potassium fluoride as fluorinating agents will produce a large amount of solid waste in large-scale production, and the stacking, storage, and treatment of solid waste will increase production costs. Therefore, it is urgent to develop a method for efficiently preparing ethoxy pentafluorocyclotriphosphazene.

[0004] Therefore, the research purpose of the present invention is to design a method for preparing ethoxypentafluorocyclotriphosphazene with high conversion rate, good yield, short reaction time, simple operation and high safety factor of low-temperature reaction. Summary of the invention

[0005] In view of the technical problems existing in the above-mentioned prior art, the present invention provides a method for preparing ethoxypentafluorocyclotriphosphazene, which can effectively solve the technical problems existing in the above-mentioned prior art.

[0006] The technical solution of the present invention is:

[0007] A method for preparing ethoxy pentafluorocyclotriphosphazene comprises the following specific steps:

[0008] S1, dissolving hexafluorocyclotriphosphazene in a solvent, and stirring uniformly at a temperature of -20 to 10° C. to prepare a hexafluorocyclotriphosphazene solution;

[0009] S2, dissolving ethanol salt in a solvent to prepare an ethanol salt solution and lowering the temperature thereof to -20 to 10°C;

[0010] S3, adding the ethanol salt solution prepared in step S2 to the hexafluorocyclotriphosphazene solution prepared in step S1 at a certain rate, stirring and reacting, the reaction temperature is -20 to 10° C., and the reaction time is 2 to 5 hours;

[0011] S4, after the reaction in step S3 is completed, the reaction liquid is subjected to solid-liquid separation, the solid matter is dried and recovered, and all the reaction liquid is collected;

[0012] S5, subjecting the reaction solution collected in step S4 to rotary distillation and separating the solvent, and subjecting the obtained mother liquor to vacuum distillation to obtain the product ethoxypentafluorocyclotriphosphazene, wherein both the rotary distillation and vacuum distillation processes need to be carried out under the protection of corresponding inert gas.

[0013] The solvent in step S1 is one or more of cyclohexane, n-hexane, acetonitrile, ethylene glycol dimethyl ether, and ethanol; and the amount of solvent added is sufficient to prevent hexafluorocyclotriphosphazene from crystallizing at low temperatures.

[0014] The solvent used in step S2 is the same as the solvent in step S1, the ethanolate is one or more of potassium ethanolate, lithium ethanolate or sodium ethanolate, and the amount of solvent added can completely dissolve the ethanolate to near saturation.

[0015] The molar mass ratio of hexafluorocyclotriphosphazene to ethanolate in step S3 is 1:1-1:2.

[0016] The step S3 is implemented by using the following ethoxy pentafluorocyclotriphosphazene preparation equipment, the ethoxy pentafluorocyclotriphosphazene preparation equipment comprises

[0017] Jacketed reactor;

[0018] The stirring mechanism comprises a driving shaft installed in the jacketed reactor and driven to rotate by a corresponding driving motor, and a plurality of stirring members are fixedly connected to the driving shaft in a radially distributed manner;

[0019] A jacket feeder is fixedly installed on the top of the jacket reactor, and the outer sides of the jacket feeder and the jacket reactor are both interlayered with corresponding heat exchange jackets in an interval state. The upper and lower sides of the heat exchange jacket are respectively provided with corresponding liquid inlet pipes and liquid outlet pipes, and the liquid inlet pipe is connected to an external cooling source through a corresponding low-temperature circulation pump; a corresponding liquid feed inlet is provided on the top of the jacket feeder, and a liquid feed outlet is provided at the bottom end thereof in a constricted shape, and a spherical closing member is movably provided in the jacket feeder, and the closing member is placed at the liquid feed outlet under the action of self-gravity and closes the liquid feed outlet, and the bottom of the closing member protrudes from the jacket feeder and is placed on the outer side of the liquid feed outlet, and when the closing member is pushed upward by a driving mechanism, the liquid feed outlet is opened;

[0020] The driving mechanism comprises a rotating shaft connected to the driving shaft by gear meshing transmission, a truncated cone-shaped triggering member is fixedly installed at the bottom of the rotating shaft, a plurality of hillside-shaped protrusions are circumferentially distributed and continuously spaced on the upper surface of the triggering member, the protrusions are higher than the bottom of the closing member, and the triggering member and the bottom spacing of the closing member are arranged in the gap between two adjacent protrusions; when the triggering member rotates, the closing member is intermittently pushed upward by the protrusions.

[0021] The ethoxypentafluorocyclotriphosphazene preparation equipment also includes an auxiliary driving mechanism for strengthening the driving of the trigger member to move up and down, the auxiliary driving mechanism includes an ultrasonic transducer fixedly installed at the bottom of the trigger member in an embedded manner, the trigger member and the rotating shaft are connected through a corresponding rubber member, and the ultrasonic transducer is connected to an external ultrasonic generator through a wire that passes through the rubber member and a through hole in the middle of the rotating shaft.

[0022] The ethoxypentafluorocyclotriphosphazene preparation equipment also includes an auxiliary heat conduction mechanism arranged in the middle of the inner side of the jacket reactor, the drive shaft is a sandwich tube structure formed by the inner mainstream pipe and the sandwich sleeve installed on the outer side of the mainstream pipe in a spaced state, and the drive shaft is connected to the output shaft end of the drive motor through a gear meshing transmission method; the stirring member is a hollow tubular structure or a hollow plate structure, and its lower end portion is constricted and bent in the same direction, the bottom of the stirring member is interconnected and supported by the mainstream pipe through a corresponding first connecting member, and the top of the stirring member is interconnected and supported by the sandwich sleeve through a corresponding second connecting member, and the top of the mainstream pipe of the drive shaft and the bottom of the sandwich sleeve are connected to an external cooling source through corresponding rotary joints and low-temperature circulation pumps.

[0023] The stirring speed of step S3 is 20-100 rad / min.

[0024] The solid-liquid separation in step S4 can be carried out by natural sedimentation, suction filtration or centrifugation.

[0025] The inert gas used in the rotary distillation of step S4 and the vacuum distillation of step S5 is one of nitrogen, helium or argon, respectively, and the inert gas used in the rotary distillation and the vacuum distillation can be the same or different.

[0026] Advantages of the present invention:

[0027] 1) The present invention prepares ethoxy pentafluorocyclotriphosphazene by a pure liquid phase method, which can not only improve the reaction conversion rate by controlling the reaction conditions and selecting the reaction solvent and ethanolate, but also further optimize the separation efficiency and product quality of vacuum distillation by introducing the means of inert gas protection. Compared with the traditional method for preparing ethoxy pentafluorocyclotriphosphazene, the ethoxy pentafluorocyclotriphosphazene prepared by the present invention has excellent quality, good mass and heat transfer, high conversion rate and good economy, and short reaction time, simple operation, high safety factor of low-temperature reaction, and has broad market application prospects.

[0028] 2) The reaction process of the present invention is realized by a newly designed ethoxy pentafluorocyclotriphosphazene preparation device. The ethoxy pentafluorocyclotriphosphazene preparation device can directly add an ethanol salt solution at a certain rate to a hexafluorocyclotriphosphazene solution for temperature-controlled stirring to prepare ethoxy pentafluorocyclotriphosphazene. During the preparation process, the hexafluorocyclotriphosphazene solution is added to a jacket reactor, the ethanol salt solution is placed in a jacket feeder, and a coolant is circulated into the heat exchange jacket during the reaction process by a low-temperature circulation pump to accurately control the reaction temperature and ensure that the reaction is carried out at a low temperature; during the preparation and stirring process, the ethanol salt solution is placed, kept warm and added at a certain rate by the jacket feeder, and a trigger member is connected by a gear meshing transmission to drive the trigger member to rotate. A plurality of hillside-shaped protrusions are circumferentially distributed and continuously spaced on the upper surface of the trigger member, and the protrusions are higher than the bottom of the spherical closing member in the jacket feeder; when the trigger member rotates, the closing member is intermittently pushed upward by the protrusions, and when the closing member is in the gap between two adjacent protrusions, it falls down under the action of gravity and closes the liquid outlet, so as to ensure that the ethanol salt solution is discharged at a certain rate. More importantly, the discharged ethanol salt solution drips onto the rotating and truncated cone-shaped trigger member, forming an umbrella-shaped downwardly distributed three-dimensional centrifugal dispersion, which promotes the improvement of the uniformity of dripping and mixing of the ethanol salt solution. Compared with the unidirectional dripping of the flow valve and the traditional plane centrifugal dispersion, the mixing uniformity of the ethanol salt solution and the hexafluorocyclotriphosphazene solution is further promoted, and the practical effect of the present invention is ensured.

[0029] 3) In addition to the liquid outlet at the bottom, the jacket feeder of the present invention is also provided with a plurality of secondary liquid outlets spaced apart in the circumferential direction; on the basis of ensuring that the bottom protruding liquid outlet of the spherical closing member is in contact with the protrusion of the trigger member to move upward to make way for material discharge, the volume and mass of the closing member are increased to ensure that the closing member has sufficient weight for self-repositioning, and the secondary liquid outlet can ensure smooth discharge of ethanol salt solution, thereby further achieving the practical effect of the present invention.

[0030] 4) The present invention can control the feeding rate by adjusting the frequency of pushing the closing member by setting the gear ratio of the meshing gears respectively connecting the rotating shaft and the driving shaft and setting the number of protrusions on the trigger member, and further set an auxiliary trigger mechanism, and embed an ultrasonic transducer at the bottom of the trigger member. The ultrasonic transducer transmits ultrasonic waves to the trigger member to promote the trigger member to push the closing member, thereby adjusting the feeding rate of the ethanol salt solution.

[0031] 5) In the present invention, on the basis of circulating the coolant by setting the heat exchange jacket of the jacket reactor and the jacket feeder, an auxiliary heat conduction mechanism is further added, by changing the driving shaft to a sandwich tube structure formed by the cooperation of the inner main flow pipe and the outer sandwich jacket, and setting the stirring element to a hollow tubular or hollow plate structure, and then supporting and connecting the bottom of the main flow pipe and the stirring element by the first connecting piece, and supporting and connecting the top of the sandwich jacket and the stirring element by the second connecting piece, so that heat exchange is carried out in multiple directions in the middle and periphery of the jacket reactor, and cooling is accelerated while stirring, so as to obtain high-quality ethoxypentafluorocyclotriphosphazene. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic structural diagram of the equipment for preparing ethoxypentafluorocyclotriphosphazene of the present invention.

[0033] Figure 2 It is a cross-sectional view of the equipment for preparing ethoxy pentafluorocyclotriphosphazene of the present invention.

[0034] Figure 3 The present invention is a schematic diagram of the installation of a jacket feeder and a trigger member of the ethoxypentafluorocyclotriphosphazene preparation device.

[0035] Figure 4 for Figure 3 Schematic diagram of the structure of the liquid outlet of the middle jacket feeder.

[0036] Figure 5 It is a process flow chart of the purification process of the present invention. DETAILED DESCRIPTION

[0037] In order to facilitate understanding by those skilled in the art, the structure of the present invention is further described in detail with reference to the embodiments in conjunction with the accompanying drawings:

[0038] Example 1

[0039] refer to Figure 1-4 , an ethoxy pentafluorocyclotriphosphazene preparation device, comprising

[0040] A jacketed reactor 1, wherein the jacketed reactor is provided with a corresponding thermometer;

[0041] The stirring mechanism comprises a driving shaft 3 installed in the jacketed reactor 1 and driven to rotate by a corresponding driving motor 2, and a plurality of stirring members 4 are fixedly connected to the driving shaft 3 in a radially distributed manner;

[0042] A jacket feeder 5 is fixedly installed on the top of the jacket reactor 1. The outer sides of the jacket feeder 5 and the jacket reactor 1 are both interlayered with corresponding heat exchange jackets in an interval state. The upper and lower sides of the heat exchange jacket are respectively provided with corresponding liquid inlet pipes and liquid outlet pipes, and the liquid inlet pipe is connected to the external cooling source through the corresponding low-temperature circulation pump 6; the top of the jacket feeder 5 is provided with a corresponding liquid inlet, and the bottom end thereof is in a constricted shape and is provided with a liquid outlet 501. A spherical closing member 7 is movably provided in the jacket feeder 5. The closing member 7 is placed at the liquid outlet 501 under the action of gravity and closes the liquid outlet 501. The bottom of the closing member 7 protrudes from the jacket feeder 5 and is placed on the outside of the liquid outlet 501. When the closing member 7 is pushed upward by the driving mechanism, the liquid outlet 501 is opened.

[0043] The driving mechanism comprises a rotating shaft 8 connected to the driving shaft 3 by gear meshing transmission, a truncated cone-shaped triggering member 9 is fixedly mounted at the bottom of the rotating shaft 8, a plurality of hillside-shaped protrusions 901 are circumferentially distributed and continuously spaced on the upper surface of the triggering member 9, the protrusions 901 are higher than the bottom of the closing member 7, and the triggering member 9 located in the gap between two adjacent protrusions 901 is spaced from the bottom of the closing member 7; when the triggering member 9 rotates, the closing member 7 is intermittently pushed upward by the protrusions 901;

[0044] The temperature tester is installed in the jacket reactor 1 and is used to detect the real-time temperature in the jacket reactor 1 .

[0045] The reaction process of the present invention is realized by a newly designed ethoxy pentafluorocyclotriphosphazene preparation device. The ethoxy pentafluorocyclotriphosphazene preparation device can directly add an ethanol salt solution to a hexafluorocyclotriphosphazene solution at a certain rate for temperature-controlled stirring to prepare the ethoxy pentafluorocyclotriphosphazene. During the preparation process, the hexafluorocyclotriphosphazene solution is added to a jacket reactor 1, the ethanol salt solution is placed in a jacket feeder 5, and a coolant is circulated into the heat exchange jacket during the reaction process by a low-temperature circulation pump 6 to accurately control the reaction temperature and ensure that the reaction is carried out at a low temperature; during the preparation and stirring process, the jacket feeder 5 is used to place, keep warm and add the ethanol salt solution at a certain rate, and a trigger member 9 is connected to the trigger member 9 by a gear meshing transmission mode, and the trigger member 9 is driven to rotate, and the reaction is carried out by a low-temperature circulation pump 6. The upper surface of the trigger member 9 is circumferentially distributed and continuously spaced with a plurality of hillside-shaped protrusions, which are higher than the bottom of the spherical closing member 7 in the jacket feeder 5; when the trigger member 9 rotates, the closing member 7 is intermittently pushed upward by the protrusions, and when the closing member 7 is in the gap between two adjacent protrusions, it falls down under the action of gravity and closes the liquid outlet 501, so as to ensure that the ethanol salt solution is discharged at a certain rate. More importantly, the discharged ethanol salt solution drips onto the rotating and truncated cone-shaped trigger member 9, forming an umbrella-shaped downwardly distributed three-dimensional centrifugal dispersion, which promotes the uniformity of dripping and mixing of the ethanol salt solution. Compared with the unidirectional dripping of the flow valve and the traditional planar centrifugal dispersion, it further promotes the mixing uniformity of the ethanol salt solution and the hexafluorocyclotriphosphazene solution, thereby ensuring the practical effect of the present invention.

[0046] The jacket feeder 5 is provided with a plurality of corresponding secondary liquid outlets 502 spaced apart in the circumferential direction above the liquid outlet 501. The closing member 7 is placed at the liquid outlet 501 under the action of its own gravity and closes the secondary liquid outlet 502. When the closing member 7 is pushed upward by the driving mechanism, the secondary liquid outlet 502 is opened.

[0047] In addition to the liquid outlet 501 at the bottom, the jacket feeder 5 of the present invention is also provided with a plurality of secondary liquid outlets 502 spaced apart in the circumferential direction; on the basis of ensuring that the bottom protruding liquid outlet 501 of the spherical closing member 7 is in contact with the protrusion of the trigger member 9 to move upward to make way for material discharge, the volume and mass of the closing member 7 are increased to ensure that the closing member 7 has sufficient weight for self-repositioning, and the secondary liquid outlet 502 can ensure smooth discharge of ethanol salt solution, thereby further achieving the practical effect of the present invention.

[0048] The reaction device also includes an auxiliary driving mechanism for strengthening the driving of the trigger member 9 to move up and down, and the auxiliary driving mechanism includes an ultrasonic transducer 10 fixedly installed at the bottom of the trigger member 9 in an embedded manner. The trigger member 9 is connected to the rotating shaft 8 through a corresponding rubber member 15, and the ultrasonic transducer 10 is connected to an external ultrasonic generator through a wire passing through the rubber member 15 and a through hole in the middle of the rotating shaft 8.

[0049] The present invention can control the feeding rate by adjusting the frequency of pushing the closing member 7 by setting the gear ratio of the meshing gears respectively connecting the rotating shaft 8 and the driving shaft 3 and setting the number of protrusions on the trigger member 9. In addition, an auxiliary trigger mechanism is further provided, and an ultrasonic transducer 10 is embedded in the bottom of the trigger member 9. The ultrasonic transducer 10 transmits ultrasonic waves to the trigger member 9 to promote the trigger member 9 to push the closing member 7, thereby adjusting the feeding rate of the ethanol salt solution.

[0050] The reaction equipment also includes an auxiliary heat conduction mechanism arranged in the middle of the inner side of the jacket reactor 1, the drive shaft 3 is a sandwich tube structure formed by the inner mainstream pipe 301 and the sandwich sleeve 302 installed on the outer side of the mainstream pipe 301 in an interval state, and the drive shaft 3 is connected to the output shaft end of the drive motor 2 by gear meshing transmission; the stirring member 4 is a hollow tubular structure or a hollow plate structure and its lower end portion is constricted and bent in the same direction respectively, the bottom of the stirring member 4 is interconnected and supported by the mainstream pipe 301 through the corresponding first connecting member 13, and the top of the stirring member 4 is interconnected and supported by the sandwich sleeve 302 through the corresponding second connecting member 14, and the top of the mainstream pipe 301 of the drive shaft 3 and the bottom of the sandwich sleeve 302 are connected to an external cooling source through corresponding rotary joints and a low-temperature circulation pump 6.

[0051] The present invention further adds an auxiliary heat conduction mechanism on the basis of circulating the coolant by setting the heat exchange jacket of the jacket reactor 1 and the jacket feeder 5, and by changing the drive shaft 3 into a sandwich tube structure formed by the cooperation of the inner main flow pipe 301 and the outer sandwich sleeve 302, and setting the stirring member 4 into a hollow tubular or hollow plate structure, and then supporting and connecting the main flow pipe 301 and the bottom of the stirring member 4 through the first connecting member, and supporting and connecting the sandwich sleeve 302 and the top of the stirring member 4 through the second connecting member, so that heat exchange is carried out in multiple directions in the middle and periphery of the jacket reactor 1, and cooling is carried out while stirring, so as to accelerate the cooling uniformity effect and obtain high-quality ethoxy pentafluorocyclotriphosphazene.

[0052] Example 2

[0053] refer to Figure 5 , a method for preparing ethoxy pentafluorocyclotriphosphazene, comprising the following specific steps:

[0054] S1, placing a container containing magnetite, 150L acetonitrile and 26kg hexafluorocyclotriphosphazene (about 100mol) in a cold trap of a low-temperature circulation pump and stirring for 10min until a hexafluorocyclotriphosphazene solution is uniformly prepared, and the temperature is set to -10°C;

[0055] S2, dissolving 8 kg of sodium ethoxide (about 120 mol) in 350 L of acetonitrile to prepare a sodium ethoxide solution, and lowering the temperature thereof to -10°C;

[0056] S3, adding the sodium ethoxide solution prepared in step S2 to the hexafluorocyclotriphosphazene solution prepared in step S1 at a certain rate, stirring and reacting, ensuring that the temperature displayed by the thermometer is stable at -10°C, the entire dropping process lasts for 1 hour, and after the dropping is completed, continuing the reaction for 2 hours;

[0057] S4, the reaction is completed, the reaction liquid is cooled to room temperature and filtered, the solid is dried and recovered, the liquid is subjected to rotary distillation under nitrogen protection to separate the solvent, and after the rotary distillation is completed, the mother liquor is transferred to a distillation tower and distilled under reduced pressure at 3000Pa under nitrogen protection to obtain the product ethoxypentafluorocyclotriphosphazene.

[0058] Example 3

[0059] refer to Figure 5 , a method for preparing ethoxy pentafluorocyclotriphosphazene, comprising the following specific steps:

[0060] S1, placing a container containing magnetite, 150L of ethylene glycol dimethyl ether and 26kg of hexafluorocyclotriphosphazene (about 100 mol) in a cold trap of a low-temperature circulation pump and stirring for 10 minutes until a hexafluorocyclotriphosphazene solution is uniformly prepared, and the temperature is set to -10°C;

[0061] S2, dissolving 8 kg of lithium ethoxide (about 120 mol) in 200 L of ethylene glycol dimethyl ether that had been refrigerated in a refrigerator for 2 h to prepare a lithium ethoxide solution, and lowering the temperature to 5°C;

[0062] S3, adding the ethanol lithium solution prepared in step S2 to the hexafluorocyclotriphosphazene solution prepared in step S1 at a certain rate and stirring to react, ensuring that the temperature displayed by the thermometer is stable at 5° C. The entire dropwise addition process lasts for 1 hour. After the dropwise addition is completed, the reaction is continued for 4 hours;

[0063] S4, the reaction is completed, the reaction liquid is cooled to room temperature and filtered, the solid is dried and recovered, the liquid is subjected to rotary distillation under argon protection to separate the solvent, and after the rotary distillation is completed, the mother liquor is transferred to a distillation tower and distilled under reduced pressure at 3000Pa under nitrogen protection to obtain the product ethoxypentafluorocyclotriphosphazene.

[0064] Example 4

[0065] refer to Figure 5, a method for preparing ethoxy pentafluorocyclotriphosphazene, comprising the following specific steps:

[0066] S1, placing a container containing magnetite, 150L ethanol and 26kg hexafluorocyclotriphosphazene (about 100mol) in a cold trap of a low-temperature circulation pump and stirring for 10min until a hexafluorocyclotriphosphazene solution is uniformly prepared, and the temperature is set to -10°C;

[0067] S2, dissolving 8 kg of sodium ethoxide (about 120 mol) in 200 L of ethanol to prepare a sodium ethoxide solution, and lowering the temperature to 0°C;

[0068] S3, adding the sodium ethoxide solution prepared in step S2 to the hexafluorocyclotriphosphazene solution prepared in step S1 at a certain rate, stirring and reacting, ensuring that the temperature displayed by the thermometer is stable at 0° C. The entire dropping process lasts for 1 hour. After the dropping is completed, continue the reaction for 5 hours;

[0069] S4, the reaction is completed, the reaction liquid is cooled to room temperature and filtered, the solid is dried and recovered, the liquid is subjected to rotary distillation under the protection of helium to separate the solvent, and after the rotary distillation is completed, the mother liquor is transferred to a distillation tower and distilled under reduced pressure at 3000Pa under the protection of helium to obtain the product ethoxypentafluorocyclotriphosphazene.

[0070] Example 5

[0071] refer to Figure 5 , a method for preparing ethoxy pentafluorocyclotriphosphazene, comprising the following specific steps:

[0072] S1, placing a container containing magnetite, 150L of n-hexane and 26kg of hexafluorocyclotriphosphazene (about 100mol) in a cold trap of a low-temperature circulation pump and stirring for 10min until a hexafluorocyclotriphosphazene solution is uniformly prepared, and the temperature is set to -10°C;

[0073] S2, dissolving 8 kg potassium ethoxide (about 120 mol) in 300 L n-hexane to prepare sodium ethoxide solution, and lowering its temperature to -20°C;

[0074] S3, adding the potassium ethoxide solution prepared in step S2 to the hexafluorocyclotriphosphazene solution prepared in step S1 at a certain rate and stirring to react, ensuring that the temperature displayed by the thermometer is stable at -20°C, the entire dropping process lasts for 1 hour, and after the dropping is completed, continuing the reaction for 3 hours;

[0075] S4, the reaction is completed, the reaction liquid is cooled to room temperature and filtered, the solid is dried and recovered, the liquid is subjected to rotary distillation under nitrogen protection to separate the solvent, and after the rotary distillation is completed, the mother liquor is transferred to a distillation tower and distilled under reduced pressure at 3000Pa under nitrogen protection to obtain the product ethoxypentafluorocyclotriphosphazene.

[0076] The content of ethoxypentafluorocyclotriphosphazene prepared according to the method of Examples 1-4 was determined by GC-MS, and the yield of ethoxypentafluorocyclotriphosphazene was calculated based on the molar amount of hexafluorocyclotriphosphazene. The results are shown in Table 1.

[0077] Table 1 Recovery of ethoxy pentafluorocyclotriphosphazene in each embodiment

[0078]

[0079]

[0080] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing ethoxy pentafluorocyclotriphosphazene, characterized in that: The specific steps include: S1, dissolving hexafluorocyclotriphosphazene in a solvent, and stirring uniformly at a temperature of -20 to 10° C. to prepare a hexafluorocyclotriphosphazene solution; S2, dissolving ethanol salt in a solvent to prepare an ethanol salt solution and lowering the temperature thereof to -20 to 10°C; S3, adding the ethanol salt solution prepared in step S2 to the hexafluorocyclotriphosphazene solution prepared in step S1 at a certain rate, stirring and reacting, the reaction temperature is -20 to 10° C., and the reaction time is 2 to 5 hours; S4, after the reaction in step S3 is completed, the reaction liquid is subjected to solid-liquid separation, the solid matter is dried and recovered, and all the reaction liquid is collected; S5, subjecting the reaction solution collected in step S4 to rotary distillation and separating the solvent, and subjecting the obtained mother liquor to vacuum distillation to obtain the product ethoxypentafluorocyclotriphosphazene, wherein both the rotary distillation and vacuum distillation processes need to be carried out under the protection of corresponding inert gas.

2. The method for preparing ethoxy pentafluorocyclotriphosphazene according to claim 1, characterized in that: The solvent in step S1 is one or more of cyclohexane, n-hexane, acetonitrile, ethylene glycol dimethyl ether, and ethanol; and the amount of solvent added is sufficient to prevent hexafluorocyclotriphosphazene from crystallizing at low temperatures.

3. The method for preparing ethoxy pentafluorocyclotriphosphazene according to claim 1, characterized in that: The solvent used in step S2 is the same as the solvent in step S1, the ethanolate is one or more of potassium ethanolate, lithium ethanolate or sodium ethanolate, and the amount of solvent added can completely dissolve the ethanolate to near saturation.

4. The method for preparing ethoxy pentafluorocyclotriphosphazene according to claim 1, characterized in that: The molar mass ratio of hexafluorocyclotriphosphazene to ethanolate in step S3 is 1:1-1:

2.

5. The method for preparing ethoxy pentafluorocyclotriphosphazene according to claim 1, characterized in that: The step S3 is implemented by using the following ethoxy pentafluorocyclotriphosphazene preparation equipment, the ethoxy pentafluorocyclotriphosphazene preparation equipment comprises Jacketed reactor; The stirring mechanism comprises a driving shaft installed in the jacketed reactor and driven to rotate by a corresponding driving motor, and a plurality of stirring members are fixedly connected to the driving shaft in a radially distributed manner; A jacket feeder is fixedly installed on the top of the jacket reactor, and the outer sides of the jacket feeder and the jacket reactor are both interlayered with corresponding heat exchange jackets in an interval state. The upper and lower sides of the heat exchange jacket are respectively provided with corresponding liquid inlet pipes and liquid outlet pipes, and the liquid inlet pipe is connected to an external cooling source through a corresponding low-temperature circulation pump; a corresponding liquid feed inlet is provided on the top of the jacket feeder, and a liquid feed outlet is provided at the bottom end thereof in a constricted shape, and a spherical closing member is movably provided in the jacket feeder, and the closing member is placed at the liquid feed outlet under the action of self-gravity and closes the liquid feed outlet, and the bottom of the closing member protrudes from the jacket feeder and is placed on the outer side of the liquid feed outlet, and when the closing member is pushed upward by a driving mechanism, the liquid feed outlet is opened; The driving mechanism comprises a rotating shaft connected to the driving shaft by gear meshing transmission, a truncated cone-shaped triggering member is fixedly installed at the bottom of the rotating shaft, a plurality of hillside-shaped protrusions are circumferentially distributed and continuously spaced on the upper surface of the triggering member, the protrusions are higher than the bottom of the closing member, and the triggering member and the bottom spacing of the closing member are arranged in the gap between two adjacent protrusions; when the triggering member rotates, the closing member is intermittently pushed upward by the protrusions.

6. The method for preparing ethoxy pentafluorocyclotriphosphazene according to claim 5, characterized in that: The ethoxypentafluorocyclotriphosphazene preparation equipment also includes an auxiliary driving mechanism for strengthening the driving of the trigger member to move up and down, the auxiliary driving mechanism includes an ultrasonic transducer fixedly installed at the bottom of the trigger member in an embedded manner, the trigger member and the rotating shaft are connected through a corresponding rubber member, and the ultrasonic transducer is connected to an external ultrasonic generator through a wire that passes through the rubber member and a through hole in the middle of the rotating shaft.

7. The method for preparing ethoxy pentafluorocyclotriphosphazene according to claim 6, characterized in that The ethoxypentafluorocyclotriphosphazene preparation equipment also includes an auxiliary heat conduction mechanism arranged in the middle of the inner side of the jacket reactor, the drive shaft is a sandwich tube structure formed by the inner mainstream pipe and the sandwich sleeve installed on the outer side of the mainstream pipe in an interval state, and the drive shaft is connected to the output shaft end of the drive motor through a gear meshing transmission method; the stirring member is a hollow tubular structure or a hollow plate structure and its lower end portion is constricted and bent in the same direction respectively, the bottom of the stirring member is interconnected and supported by the mainstream pipe through a corresponding first connecting member, and the top of the stirring member is interconnected and supported by the sandwich sleeve through a corresponding second connecting member, and the top of the mainstream pipe of the drive shaft and the bottom of the sandwich sleeve are connected to an external cooling source through corresponding rotary joints and low-temperature circulation pumps.

8. The method for preparing ethoxy pentafluorocyclotriphosphazene according to claim 1, characterized in that: The stirring speed of step S3 is 20-100 rad / min.

9. The method for preparing ethoxy pentafluorocyclotriphosphazene according to claim 1, characterized in that: The solid-liquid separation in step S4 can be carried out by natural sedimentation, suction filtration or centrifugation.

10. The method for preparing ethoxy pentafluorocyclotriphosphazene according to claim 1, characterized in that: The inert gas used in the rotary distillation of step S4 and the vacuum distillation of step S5 is one of nitrogen, helium or argon, respectively, and the inert gas used in the rotary distillation and the vacuum distillation can be the same or different.

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